1. Field of the Invention
The present invention relates to a heat exchanger which is suited for use for example as a condenser or evaporator employed in the car cooler or room air conditioning system, or as an oil cooler.
2. Description of the Prior Art
The heat exchanger of this type may, in a case, comprise brackets which are attached to its headers for mounting it on an object such as an automobile body. In a further case, the heat exchanger may also comprise pipe joints which are attached to its headers in order to connect some external pipings to the headers in fluid communication therewith.
In the former case wherein the brackets are incorporated, they are usually metal plates formed by the pressing method and secured to a body of the heat exchanger. For example, those brackets are spot-welded to the headers of the so-called multi-flow type heat exchanger, which comprises flat tubes disposed in parallel with one another and each having both ends connected to a left and right hollow headers in fluid communication with them.
If such plate-like brackets are spot-welded to the headers, particularly to the headers which are pipes round in cross section, then the contact between them cannot be of a sufficiently large area. Thus, it has been observed that vibration of an engine or automobile body causes the junction to be broken before long. There are further problems that stress concentration occurring in the headers is apt to deform them, and that the positioning or temporary setting of the headers cannot be done easily when welding.
In the latter case wherein the pipe joints are connected, a typical example of such pipe joints comprises, as shown in FIG. 14, a short pipe 251 having an end connected to the header 203 and a flared joint 252 integral with another end of the short pipe. Another mating joint attached to an end of the external piping may be connected to the flared joint 252 so as to form a coolant circulation path together with a compressor or the like.
However, this conventional structure is can not necessarily provide a junction having a sufficient surface area between the flared joint 252 and short pipe 251, or between the short pipe 251 and a wall of the header 203. Thus, there is a possibility that the attached flared joint 252 cannot be regarded as durable and rigid enough under some conditions. A bracket may, in such a case, be used to consolidate the flared joint 252 with the heat exchanger body, thereby resulting in the undesirable increase in the number of constituent parts of the heat exchanger.